VATICAN CITY — Pope John Paul II body was carried ceremoniously Monday into St. Peter's Basilica, where it will lie in state for public viewing until Thursday evening.

NBC News' Keith Miller explains the significance of the procession and explains what will happen next in terms of the start of the Conclave to choose the next leader of the Roman Catholic Church.

What is the mood in St. Peter’s today with pilgrims lining up to see the pope lying in state?
Well it’s interesting; it’s not particularly sad at the moment, but I imagine that once his body is lying in state, the mood will change as people get closer to St. Peter’s Basilica where he will be.

There are lots and lots of people. Certainly as many people as I’ve seen in this square in more than a decade. I think that we will see an overflowing crowd. The lines are going to be massive. There is a lot of reverence; people really want to pay their respects personally.

The Vatican realizes that the numbers that are expected are quite phenomenal. So they are actually going to leave the basilica open for 21 hours at a time. They will just be closing it for three hours a day to clean the basilica. Otherwise it will be open until Thursday evening before the funeral on Friday.

At the moment, they are planning on having the funeral on the steps of St. Peter’s Square — just in front of the basilica. Depending on the weather — it looks like it will be favorable — so that’s what they are planning on. If it were a torrential downpour they may think about moving it inside.

But, they want to accommodate as many people as they can. You can get about 100,000 people into St. Peter’s Square. I noticed today that they set up television monitors on the main streets leaving out of St. Peter’s Square. So, they are expecting an overflow capacity to participate in the pope’s funeral.

Can you describe the diversity of the crowd? Does it really look like a global outpouring?
Well, St. Peter’s Square has always been a global magnet, just because of the reach of the Roman Catholic Church with over a billion members. They now have cardinals arriving in town and they represent over 66 different nations.

So, just by its very nature the Roman Catholic Church has turned into a very diverse, global organization. With that in mind, people who come to Rome on any given day tend to represent dozens and dozens of different nations.

What will be significant is that this particular pope, who traveled to more than a hundred countries, made personal contact with such a diverse group of people and cultures.

There will probably be some person representing each of those different countries here to pay their respects. I think just about every nationality on the planet will here at one point or another over the next three days.

Can you explain the significance of the process we saw today?
Pope John Paul II was the 264th pope to reign over the Vatican. So, there is a lot of history, a lot pageantry, a lot of formality involved in burying a pope.

On Monday, his body was moved from the Apostolic Palace, where it has been lying in state for members of the Vatican staff and high-ranking Italian and other political officials.

It was moved through the bronze doors, down through St. Peter’s Square, then up the steps through the massive bronze doors of the basilica itself. It was an extremely moving ceremony, full of symbolism.

Over the next five days we will see lots of symbolism. The church is very good at it and knows how to conduct this sort of ceremony with dignity — all the way through the high funeral mass that will be held in St. Peter’s Basilica on Friday.

It’s interesting that even the future King of England
has rescheduled his wedding plans
because of the date of the funeral. It was going to coincide with his wedding to Camilla Parker Bowles and it did not seem appropriate to him.

So, not just ordinary people, and us journalists are affected by the pope’s death, but it goes right on up to monarchy.

Today was the cardinals first meeting since the pope’s passing. What did they discuss? Basically they met for about two and a half hours. This is the Congregation of Cardinals. They are all part of the College of Cardinals, but they call this particular meeting the Congregation of Cardinals.

They will come together every day now until they elect a new pope. Basically, they will talk about the administrative running of the church, about procedures. Most importantly, they made the decisions on Monday about where the pope will be buried, how the funeral will take place, and how the funeral will take place. They will also set a date for when the Conclave will begin.

So, they will meet every single day before the Conclave begins. Given the size of the church, they need some sort of apparatus to continue the day-to-day operations of the church and that is what they are doing.

The next most important thing they will be doing is actually setting a date for the Conclave to begin. That will probably come a little later, because they will basically gage how many cardinals are making it into town.

They have 183 cardinals, many of them are over the age of 80 and also frail and in poor health, as was the pope, and probably won’t be able to make it here. For the electors, the cardinals who are eligible to vote, there are 117 of them. Not all of them will be able to make it either, perhaps. There could be one or two who are ill, or who have some sort of calamity in their personal lives that will prevent them from traveling here. But, certainly ever able-bodied cardinal will try to make his way to St. Peter’s Square.

Once they figure out how many cardinals are here, or on their way here, then they can probably get closer to setting a date for the Conclave.

How much politicking among the cardinals will go on over the next few days?There will probably not be as much of that now because of the reverence that they will pay to the pope who has just passed. They will probably be keeping a low profile.

But, the politicking has been going on for some time. In many ways, it is never ending. The cardinals are always sizing up each other. You have to keep in mind that these guys are highly, highly intelligent men. Many of them have multiple doctorate degrees in theology and philosophy. They are very intelligent men and also devoutly spiritual and have completely given their lives to the church.

At the same time, they are humans and they are engaged in politics and partly engaged in politics all the time. That may be suspended for the next couple of days as they pay homage to Pope John Paul II.

But, they will be sizing each other up. Don’t get me wrong. They will be taking each others measure over the next couple of days. Just seeing who is conducting themselves properly in public, who isn’t. Who is grand-standing, who isn’t. There are a lot of variables that go into electing a pope. Those variables are being defined and in some ways even acted out even as we watch the burial of this pope.